Wet lime screener



Sept. 6, 1966 J. VAN BAEL WET LIME S REENER Filed NOV. 18, 1963 FIG.5.

FIG.4.

INVENTOR.

JOSEPH VAN BAEL B 9' L l m ATTO R N S United States Patent 3,271,012 WET LIME SCREENER Joseph Van Bael, 37426 Lakeshore Drive, Mount Clemens, Mich. Filed Nov. 18, 1963, Ser. No. 324,346 16 Claims. (Cl. 259-29) The present invention relates to a wet lime screener and more particularly, to a power driven screener designed especially for sifting hydrated lime for use in plastering.

It is an object of the present invention to provide a screener of the character described in which the screener hopper is resiliently mounted for a particular movement designed to produce the most efficient sifting action.

More specifically, it is an object of the present invention to provide a power actuated screener including a hopper, resilient means mounting the hopper for transverse sifting movement, and centrifugally operating agitating means fixed to said hopper for imparting a particular screening movement thereto.

It is a feature of the present invention to provide a screener of the character described comprising an open frame, a hopper having a screen bottom, resilient means in the form of C-shaped springs interconnecting the hopper and frame, and centrifugally operating actuating means rigidly fixed to and movable with said hopper.

It is a further feature of the present invention to provide a screener as described in the preceding paragraph in which the C-shaped springs are positioned to occupy planes parallel to the ends of the hopper and are preferably formed of round bar stock,

It is a further feature of the present invention to provide a screener as described in either of the two preceding paragraphs which includes a motor fixed to the frame and a flexible coupling between the motor and the centrifugal actuating means.

It is a further object of the present invention to provide a resiliently mounted hopper, an elongated centrifugally operating agitating member, means mounting said member for rotation about an axis, one end portion of said elongated member having a center of gravity spaced radially from the axis of rotation of said member, the other end portion of said elongated member having a center of gravity spaced radially from the axis of rotation of said member and additionally spaced circumferentially around the axis of rotation of saidmember about 90 degrees from the center of gravity of the first mentioned portion.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a perspective view of the screener.

FIGURE 2 is an enlarged sectional view through the centrifugally operating agitator.

FIGURE 3 is a sectional view on the line 33, FIG- URE 2.

FIGURES 4 and 5 are sectional views on the lines 4--4 and 5-5 respectively, of FIGURE 2.

Referring now to the drawing, the screener comprises a rigid frame indicated generally at comprising two elongated side bars 12 and 14 which conveniently may be formed of angle iron as illustrated in FIGURE 2, joined by transverse bars 16, 18, and 22. At one end of the frame wheels 24 are provided by means of which the entire screener assembly may be transported by lifting the rear transverse bar 22.

Intermediate the transverse bars 16 and 18 is a mounting plate 26 carrying an electric motor 28 for actuating the screener, as will subsequently be described.

3,271,012 Patented Sept. 6, 1966 ice The screener comprises a rectangular hopper 30 having end walls 32 and side walls 34, the bottom of the screener being in the form of a screen 35 which appears through a broken away opening in the side wall 34 of FIGURE 1.

The hopper 30 is mounted on the frame 10 for oscillating or screening movement relative thereto by resilient means in the form of springs 36. The springs 36 are preferably formed of cylindrical bar stock and are shaped in the form of the letter C, with the upper and lower ends thereof extending substantially horizontally. Moreover, the springs 36 all occupy planes substantially parallel to the end walls 32 of the hopper. As indicated in FIGURE 1, the lower ends of the springs are fixedly connected to the frame as indicated at 38 and the upper ends of the springs are fixedly connected to the upper edges of the end walls 32 of the hopper as indicated at 40.

With this arrangement the hopper 30 is movably mounted with reference to the fixed frame 10 and the directions of movement which are most readily permitted by the springs 36 are movements in vertical planes extending transversely with respect to the elongated frame 10. These directions as will be apparent, are parallel to the planes occupied by the C-shaped springs 36.

In order to impart the required oscillatory or screening movement to the hopper 30, agitating mechanism is provided and is in the form of an elongated cylindrical tube 42 fixedly connected to the hopper 30 along the lower edge of one side wall 34 thereof. Attachment is indicated by tabs 44 which may be welded or otherwise secured to the hopper. Within the tubular housing 42 is an elongated rotor indicated generally at 46, having journal portions 48 at its ends mounted in bearings 50 and establishing a single longitudinal axis of rotation which in FIGURES 2 and 3 is designated by the dot and dash line 52.

The elongated rotor comprises relatively large cylindrical end portions 56 and 58 each of which has its center axis displaced laterally from the axis of rotation 52. The center axis of the cylindrical portion 56, as best seen in FIGURE 4, is indicated at 60, whereas the axis of rotation 52 is in this figure illustrated as located substantially above the cylinder axis 60. The end portion 58 of the elongated rotor 46 is also cylindrical and has its cylindrical axis located at 64, as best seen in FIGURE 5, which as seen in this figure is located to the left of the axis of rotation 52. It will of course be understood that the cylindrical portions 56 and 58 are preferably formed from a single piece of material and that accordingly, the center of gravity of each cylindrical portion 56 and 58 lies along its cylindrical axis 60 or 64 respectively.

From the foregoing it will be apparent that one end portion of the rotor 46 has a center of gravity which is displaced laterally from the axis of rotation of the rotor and the other end portion of the rotor has a center of gravity which is alsodisplaced laterally from the center of rotation of the rotor and which in addition is displaced circumferentially of the axis of the rotor with respect to the center of gravity of the first end portion by about degrees.

With this arrangement of the centers of gravity of end portions of the unitary elongated rotor, it will be observed that a peculiar but highly efiicient screening motion is imparted to the hopper and that this motion is materially facilitated by the specific arrangement of the springs 36. This motion may best be understood by considering that each end portion of the centrifugal rotor, which operates particularly on the corresponding end portion of the hopper, tends to cause this end portion of the hopper to move in a circular path occupying a vertical plane. If the eccentric cylindrical portions 56 and 58 were angularly spaced apart by approximately degrees, the hopper would be oscillated in such a way that opposite ends thereof would be moving at all times in opposite directions with the result that the center of the hopper would be substantially stationary. However, with the centrifugal masses or the centers of gravity thereof spaced circumferentially or angularly of the axis of rotation of the elongated rotor by approximately 90 degrees, an entirely difierent overall motion is imparted to the hopper. When one end of the hopper is moving substantially horizontally, the opposite end of the hopper is moving substantially vertically, and with this arrangement agitation is effective throughout the entire screened bottom of the hopper, including the central portion thereof which has both vertical and horizontal components of motion.

It has been found in practice that the hopper, mounted and agitated as described in the foregoing, is particularly useful in providing a substantially uniform screening of wet lime or other material throughout the entire area of its screened bottom. In operation the motion of the Wet lime screener emulsifies the firm soaked lime and cuts and screens particles thereof.

Rotation is imparted to the elongated rotor 46 from the motor 28 by a fiexible drive shaft indicated generally at 66, the flexibility of the drive shaft of course being required because of the fact that the hopper and hence the tubular housing $2 with its bearings 50, partakes of a sifting motion including horizontal and vertical components.

The elongated rotor 46 as described herein is preferred because of the ease with which it may be machined by simple turning operations from a single bar of metal. However, it will also be appreceiated that the rotor may be assembled from a shaft on which the cylindrical portions are eccentrically mounted and which may be clamped or otherwise secured in position by appropriate means.

In the operation of this wet lime screener water is added to the lime for slaking and it is permitted to stand over-night. The next day this wet slacked lime is shoveled into the hopper of the wet lime screener which is driven or vibrated by the motor operating at a speed of between 1500 and 2000, and preferably at about 1750 rpm. This results in imparting an agitation or vibratory motion to the hopper having both vertical and horizontal components of motion, at an amplitude which increases as the load of the wet lime decreases, generally for example from to A of an inch.

The screen forming the bottom of the hopper in the wet lime screener may be the usual screen for screening wet lime; for example, /s inch mesh stainless steel gauge, i.e. having eight wires to the inch.

Due to the rapid and vigorous agitation the screening process fiuffs up the wet lime making the material softer and more pliable in use. The fluffing of the wet lime increases its bulk substantially, increases of in bulk being usual. The vigorous agitation applied by the mechanically driven screener reduces the time over hand screening very materially, savings of 60% in time being usual.

It has further been noted that the action of the wet lime screener when operated as described in the foregoing is particularly effective in breaking up particles of unslacked lime, thus substantially eliminating lime burns in subsequent plaster.

In the usual operation the wet lime after its initial screening is returned to the screener for mixing with plaster of paris to facilitate hardening of the plaster, and it has been found that savings up to 10% in the addition of plaster of paris are possible because the lime is looser and the plaster mixes to a more uniform match.

The drawing and the foregoing specification constitute a description of the improved wet lime screener in such full, clear, concise and exact terms as to enable any perl son skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A wet lime screener comprising a frame, a hopper having a screen at its bottom wall, resilient means mounting said hopper on said frame, and centrifugal agitating means connected to said hopper, said agitating means comprising elongated rotary means extending substantially front end to end of said hopper and mounted for rotation about a single axis, said rotary means comprising two masses whose centers of gravity are spaced longitudinally of said axis substantially midway between the center and ends of said hopper and further are spaced circumferentially of said axis about degrees from each other.

2. A wet lime screener comprising a frame, a hopper having a screen at its bottom wall, resilient means mounting said hopper on said frame, and centrifugal agitating means connected to said hopper, said agitating means comprising rotary means mounted for rotation about a single axis, said rotary means comprising two masses whose centers of gravity are spaced longitudinally of said axis and further are spaced circumferentially of said axis about 90 degrees from each other, said rotary means comprising an elongated rigid bar rotatably fixed to said hopper, said bar having a portion located within one longitudinal half of said bar having a center of gravity spaced radially from the axis of rotation thereof, said bar having a second portion located within the other longitudinal half of said bar having a center of gravity spaced radially of the axis of rotation and spaced circumferentially of the axis of rotation relative to the center of gravity of said first portion by about 90 degrees.

3. A wet lime screener comprising a frame, a hopper having a screen at its bottom wall, resilient means mounting said hopper on said frame, and centrifugal agi ating means connected to said hopper, said agitating means comprising rotary means mounted for rotation about a single axis, said rotary means comprising two masses whose centers of gravity are spaced longitudinally of said axis and further are spaced circumferentially of said axis about 90 degrees from each other, said rotary means comprising an elongated rigid bar rotatably fixed to said hopper, said bar having a first cylindrical portion at one side of center of said bar located eccentrically with respect to its axis of rotation, and a second cylindrical portion at the other side of center of the bar located eccentrically with respect to its axis of rotation, the axial center lines of said two cylindrical portions being spaced about the axis of rotation of said rod by about 90 degrees.

4. A wet lime screener comprising an open frame, a screen-bottom hopper, a plurality of generally C-shaped springs mounting said hopper to said frame with all of said springs occupying parallel planes, and centrifugal agitating means connected to said hopper, said agitating means comprising rotary means mounted for rotation about a single axis, said rotary means comprising two masses whose centers of gravity are substantially spaced apart longitudinally of said axis and further are spaced circumferentially of said axis about 90 degrees from each other, the axis of rotation of said rotary means being perpendicular to said parallel planes.

5. A wet lime screener comprising an open frame, a screen-bottom hopper, a plurality of generally C-shaped springs mounting said hopper to said frame with all of said springs occupying parallel planes, and centrifugal agitating means connected to said hopper, said agitating means comprising an elongated rigid bar rotatably fixed to said hopper, said bar having a portion located within one longitudinal half of said bar having a center of gravity spaced radially from the axis of rotation thereof, said bar having a second portion located within the other longitudinal half of said bar having a center of gravity spaced radially of the axis of rotation and spaced cit.-

cumferentially of the axis of rotation relative to the center of gravity of said first portion by about 90 degrees.

6. A wet lime screener comprising an open frame, a screen-bottom hopper, a plurality of generally C-shaped springs mounting said hopper to said frame with all of said springs occupying parallel planes, and centrifugal agitating means connected to said hopper, said agitating means comprising an elongated rigid bar rotatably fixed to said hopper, said bar having a first cylindrical portion at one side of center of said bar located eccentrically with respect to its axis of rotation, and a second cylindrical portion at the other side of center of the bar located eccentrically with respect to its axis of rotation, the axial center lines of said two cylindrical portions being spaced about the axis of rotation of said rod by about 90 degrees.

7. A wet lime screener comprising a horizontal open frame, a rectangular hopper having a screen bottom, C- shaped springs having their ends substantially horizontal and connected respectively to said frame and hopper, all of said springs occupying planes parallel to the end surfaces of said hopper, centrifugal agitating means rigidly connected to said hopper comprising rotary means mounted for rotation about a single axis, said rotary means comprising two masses whose centers of gravity are substantially spaced apart longitudinally of said axis and further are spaced circumferentially of said axis about 90 degrees from each other, the axis of rotation of said rotary means being perpendicular to said parallel planes.

8. A wet lime screener comprising a horizontal open frame, a rectangular hopper having a screen bottom, C- shaped springs having their ends substantially horizontal and connected respectively to said frame and hopper, all of said springs occupying planes parallel to the end surfaces of said hopper, centrifugal agitating means rigidly connected to one side of said hopper comprising an elongated substantially horizontal rigid bar rotatably fixed to said hopper, said bar having a portion located within one longitudinal half of said bar having a center of gravity spaced radially from the axis of rotation thereof, said bar having a second portion located within the other longitudinal half of said bar having a center of gravity spaced radially of the axis of rotation and spaced circumferential-ly of the axis of rotation relative to the center of gravity of said first portion by about 90 degrees.

9. A wet lime screener comprising a horizontal open frame, a rectangular hopper having a screen bottom, C- shaped springs having their ends substantially horizontal and connected respectively to said frame and hopper, all of said springs occupying planes parallel to the end surfaces of said hopper, centrifugal agitating means rigidly connected to one side of said hopper comprising an elongated substantially horizontal rigid bar rotatably fixed to said hopper, said bar having a first cylindrical portion at one side of center of said bar located eccentrically with respect to its axis of rotation, and a second cylindrical portion at the other side of center of the bar located eccentrically with respect to its axis of rotation, the axial center lines of said two cylindrical portions being spaced about the axis of rotation of said bar by about degrees.

10. A wet lime screener comprising a horizontal open frame, a rectangular hopper having a 'screen bottom, C- shaped springs having their ends substantially horizontal and connected respectively to said frame and hopper, all of said springs occupying planes parallel to the end surfaces of said hopper, centrifugal agitating means rigidly connected to one side of said hopper comprising a tubular housing fixed to one side of said hopper along the lower edge thereof, an elongated rotor journalled in said housing for rotation about an axis within said tube, said rotor having end portions whose centers of gravity are spaced radially from the axis of rotation of said rotor and are spaced from each other by about 90 degrees about the axis of rotation of said rotor.

11. A wet lime screener as defined in claim 10 which comprises a motor on said frame, and a flexible coupling connecting said motor to said rotor.

12. A wet lime screener as defined in claim 10 in which said springs are formed of resilient rod.

13. The method of screening wet lime in the process of preparation for plastering which comprises placing wet slaked lime in a hopper having a screened bottom, mechanically vibrating the hopper both horizontally and vertically at a frequency of between 1500 and 2000 strokes per minute to screen the slaked lime, break up all particles of unslaked lime, and to cause a substantial increase in volume of the unslaked lime.

14. The method as described in claim 13 in which the hopper is provided with inch mesh screen.

15. The method as defined in claim 13 in which the hopper is elongated and which comprises developing the vibration by applying separate gyratory forces to opposite end portions of the hopper each of the forces occupying planes perpendicular to the length of the hopper, the direction of the application of each of said forces being progressively changed about the longitudinal axis of the hopper, the instantaneous direction of the two forces being approximately 90 degrees out of phase with each other.

16. A screener as defined in claim 7 in which said centrifugal agitating means is rigidly connected to one side of said hopper.

References Cited by the Examiner UNITED STATES PATENTS 2,053,585 9/1936 Toepfer 209-326 2,101,03 1 12/ 1937 Little. 2,298,182 10/ 1942 Strube 209326 X 2,413,109 12/ 1946 Leipold et al 259-72 X 3,061,278 10/ 1962 Dreyer.

WALTER A. SCHEEL, Primary Examiner, JOHN M. BELL, Assistant Examiner. 

1. A WET LIME SCREENER COMPRISING A FRAME, A HOPPER HAVING A SCREEN AT ITS BOTTOM WALL, RESILIENT MEANS MOUNTING SAID HOPPER ON SAID FRAME, AND CENTRIFUGAL AGITATING MEANS CONNECTED TO SAID HOPPER, SAID AGITATING MEANS COMPRISING ELONGATED ROTARY MEANS EXTENDING SUBSTANTIALLY FROM END TO END OF SAID HOPPER AND MOUNTED FOR ROTATION ABOUT A SINGLE AXIS, SAID ROTARY MEANS COMPRISING TWO MASSES WHOSE CENTERS OF GRAVITY ARE SPACED LONGITUDINALLY OF SAID AXIS SUBSTANTIALLY MIDWAY BETWEEN THE CENTER AND ENDS OF SAID HOPPER AND FURTHER ARE SPACED CIRCUMFERENTIALLY OF SAID AXIS ABOUT 90 DEGREES FROM EACH OTHER. 